If your looking for simple, there is nothing more simple than Halo 3.

I haven't played a game for a long time without my parents, since about Super Mario Bros. 3 I think lol.

Aegis Wing
Ultimate Mortal Kombat 3
Galaga

These are the best.

quote Aussie Legend

If your looking for simple, there is nothing more simple than Halo 3.

lol

Halo 3
call of duty w@w
call of duty 3
call of duty 2(pretty much most of the call of duty games are good for parents)

how old is your dad?
did he used to have an atari or nintendo?
i would say go with Halo or street fighter 4 (yeh it's not FPS, but still fun)..but let him beat you a couple of times..
that might keep him interested at least...

I play L4D with my mum lol

The last game I played with my dad was Diddy Kong Racing when I was 5.

And it was *bleep*ing awesome.

Last game I played with my dad was conflict desert stome, loved that game. I know op flashpoint isn't an fps and it is hardcore but it is a ton of fun.

The Call of Duty games are renowned for their ease of use. I know a complete moron who loves them too, and he has the motor skills and computer knowledge of a drunken chimp.

If he liked Call of Duty 4: Modern Warfare, I'd keep with something familiar.
Call of Duty 2 for the 360 will be cheap to find, and it'll be great if he likes WWII stuff like most dads.
Otherwise maybe wait for CoD: Modern Warfare 2.

While Fallout 3 and Bioshock are also brilliant games, they have a lot of other features and attacks that may be a little too much if you want to keep the gameplay simple. Plus the CoD series is more rooted in reality, which a lot of older non-gamers prefer as a starting point.

My dad wouldn't understand me playing as a wizard fighting trolls up a mountain in Oblivion, but when he saw Call of Duty 2 he instantly recognised what it was meant to be about.

The only game I ever played with my parents was Mario Kart 64 on the nintendo 64! I still love that game but I would never play it with my dad... or anything else.

I'd go with MW2.

It occurs to me that the only game I've ever seen my technophobe dad ACTUALLY PLAY was... Wii Sports when it was brand new a couple of Christmasses ago. For one stint. Once he heard me playing Fifa 99 and rushed into the room thinking there was a footie match on haha.

Modern Warfare or Modern Warfare 2 would probably be your best bet, two of the best FPS's for the Xbox 360, and both are really easy to pick up and play.

If your Dad is into sports then sports games are always a good option (Fifa/Madden/NBA, etc).