Gamemodes!

Reverse CTF! You have to bring the flag from you base to your enemy base!

A wild King of the hill with portal aspects.

Hunt mode. Kinda like The Ship.

Hunt down one player and kill them, while avoiding getting killed by another player.

Hide and seek!

TDM where only headshot kills count.

Mower Mode: You have a yard where grass grows at a certain rate. You get a mower and a pistol. Goal is to have the longest grass at the end of the round. Mow the lawns of other people and kill them to protect your own property.

First-Person MOBA giggle

Tower Defence, you have an option to turn your weapon into a tower and place it down at a location you desire, but then you won't have the weapon anymore, if you get killed your tower goes along with you, other people can destroy your tower and towers can destroy towers, the power of each one is depended on the weapon you used to make the tower e.g you used a shotgun and you would have a tower firing bursts of bullets, assault rifle then rapid fire but weak dmg. It would be interesting since there are normally alot of weapons to choose from. You could even have other people as first person creeps!

Assault -> Complete objectives (attack a base) to gain points while the other team defends and tries to stop you.

Bombing Run -> Ball in middle of map, try and score in the other team's goal.

These were in a few versions of UT and I always enjoyed them

a capture the base one team have a base then the other team need to capture within 10 min. The team that needs to capture respawn (1 min dealy) and the team that defend have 1 life

Collecting tokens... each token makes you 10% stronger but 10% slower... there would be total of 25 tokens and first team to get 15 and get to specific location would win. You could either quickly collect all tokens or wait for other team to get them for you and kill the slowest one with most tokens and take them from his corpse ^^

I always wandered why no one created street basket in Source... Like, 3 VS 3, with various details for cartoonish players available via drops or ingame shop. That could be new TF2, just with hoops. Find 2 friends and play random strangers... or bots... or join a sponsored tournament on official servers...

If you make it we will come.

Once thought about a zombie mod, where you have been somewhat poisened, so that you loose one life each second..
And then killing zombies give you a little life.. Go beserk with that axe.. Might be boring after a while.

a dinosaur survival ^^

a paintball game (fps)

Traitor/Assault: Two teams. One has to defend its base, the other has to get inside and conquer it. One (or more, depending on the number of players on each team) player in the defending team is a traitor, though. The traitor tries to open doors, deactivate security systems, assassinate players from the defending team, &c without being seen. The mode can be made more intense by disabling respawn mid-round (depending on your game's pace ofc, as it's not much fun to just wait for the next round for 30+ minutes).

At the beginning of a match, each player is assigned a random player on the other team, and they both get set to the same class.

When the game starts, the aim is to kill a player of the same class without dieing first, or some variation thereof.

Tournement gamemode.
Several small arenas, All players fight against eachother in 1Vs1 combat in seperate arenas, win your fight to progress to the next fight repeat until the final round between the 2 best players.
Spectators would be able to view the fights going on.

Gladiator mode (1)
This is a gamemode where you are placed into an arena from the holding area (Or viewing area during a game) and are pinned up against a random player, you are only able to use melee weapons and succesful taunts give you bonus points.

Gladiator (2) This gamemode consists of being in arenas with nothing more than your melee weapons either (Or randomly) small 1V1 or 2V2 style arenas or free for all arenas.

NOTE: Viewers would be unable to do damage.

NOTE: Melee only could be changed to include guns or other such weapons.

"Flagball"

There is only 1 flag that both teams would try to capture and return to their own base. If a player is shot the flag would be placed where the flag carrier was killed. If the flag was closer to the enemy base, the other team had a better chance at getting the flag.

Like chess: Each player is a piece of a chessboard the teams, black and white, have the king who must defended, each player has particulary skill and/or weapon. The round has won from who kill the king before the others.

Something similiar to small arena? Both teams in cages getting released 1 by 1, for 1v1(Randomly). Tho dunno, there could be some other things to add this mode :/

Kill confirmed?

• Collect or Die (name work in progress xD): each team has a vehicle to "repair" in order to escape (and win); to repair it, they have to collect X (it depends on the map) number of items (like parts of the engine, fuel tanks, wheels...) from all around the map.
  So, you can decide to go finding the items or to keep the enemy away from theirs. It can be a long gamemode, so, maybe, it will need a fixed duration (like 15 minutes, complete the vehicle or collect more items).
  Only a certain class can repair the vehicle and it will take a certain ammount of time (like planting the bomb in a COD match) and when it's done all team mates have to jump inside while the other team try to destroy it.

Very bad explanation, I hope you understood.