Games for old people?

Puzzle Agent

Gothic

RollerCoaster Tycoon 1. Or 2. I liked 1 more.

>:o

http://www.alawar.com/

My dad loves the Far Cry series and Dynasty Warriors (both on PS2/3)
He's not much of a PC gamer though so... I don't know.

I went through my library and tried to find games that would fit your requirements :
Chime, Dungeon Hearts, Edge, Incredipede, Nightsky, Pac-Man Championship Edition DX+, Shatter, Spirits.
(sorry, too lazy to make all these clickies !)

You're lucky to have parents who ask for new games. My mother is stuck with that shitty Farmville...

Snuggle truck?
Maybe some turn-based strategy games?
....pokemon fire red!

How about point-and-click adventure games?

Tried roller coaster tycoon? It was hell lot of fun for me (I don't really enjoy these type of games but roller coaster tycoon is an exceptional gem)

maybe Might & Magic Clash of Heroes

I'd get some PopCap games or even complete pack when it goes on sale.

You should also try introducing them to point&click adventures.

Frogger, 7 Wonders, 6180 the moon, Beware Planet Earth, Trainz

Worms is turn-based and really fun to play if you have more than one person in the same PC as well.

PopCap and MumboJumbo games are the best for old people.

Clickr might be a good one. It's a match 4 game and seems pretty easy at first, but with all the different modes it keeps giving a challenge. It's my current addition.

Tidalis is also a good match 3 with a lot of unique features to it

My mom loves Candy Crush

dota 2

If they liked Bejewled you should give Puzzle Quest a try. There might be a lot of text in that game, but it is not very essential to read and understand.

Roguelikes offer a lot of replayability. Action oriented ones might be easier to get into, such as diablo type games. Yes, they have some kind of story as well, but it all boils down to reading numbers on equipment and selecting what you prefer.

Overlord might be another nice game to try, although it may not have the replay value you are looking for.

Other than that go for board game adaptions like the Settlers of Catan or Carcassonne. Hive just started its early access phase on steam. Those type of games have the added benefit of connecting generations of gamers, both online and offline.

Trials 2: Second Edition

It's a nice casual game.

And it will last for hundreds of hours!

Another great one is:

Hero Academy

How about FTL?

Point & click games. There are tons of pretty good older titles (e.g. Syberia and Still Life series) and brand new as well (Daedalic Entertainment productions).

How about card games? You could try Blizzard's Hearthstone, it's relatively simple for a collectible card game.