I play them solely because they are fun.

 No offense to anyone, but if you play oblivion it's because you seriously have no life and absolutely nothing better to do.  That game is so complicated it's boring, you need an extreme amount of time to do anything or get anywhere.  I LOVE RPG's, it's by far my favorite genre, and I think Oblivion is terrible.  The fact that you think that when you turn on Oblivion, to me, says that your gaming is maturing and you're having a much more adult outlook on gaming.

I'm going to get flamed for that paragraph.

I play video games because they're entertaining, and because I'm competitive and can't play soccer anymore.  I was like you Hawkeye - I used to think I played too much and that there were much more productive things I could be doing.  Then I got a girlfriend and that issue corrected itself.  I don't play near as much anymore, but my girlfriend likes to play video games a little bit too.  She actually asked me if I owned Resistance - my jaw dropped...

Now, I play for socialization.  I'm still competitive, but I have a group of 4 friends I hang out with.  Unfortunately, one lives 2 hours in one direction, one 2 hours in the other direction, and the other 2 within an hour from me.  It's pretty hard for us to all get together anymore because of distance and family (one just had his first child, another just had his 2nd), so we play on XBOX Live together.  Honestly, if I didn't play games with them, I'd probably very very rarely play them anymore, only whenever my girlfriend wanted to.

Lastly..sports are boring?  Hmm..ok?  Football is awesome.  If it's sunday, I don't care what's going on outside of my living room if the Saints are playing.  If others want to come and watch, fine, but they know if they're interupting the game, they aren't welcome here.  I'm a bit of a die-hard fan - especially of football, it's the most team-oriented sport on earth.  Twenty-two people on the field at a time, and if one misses their asignment it's a domino effect.  It's a precision game where only the best come out on top..if you don't win, chances are you didn't deserve to.  Trust me, I'm a Saints fan, I've accepted that fact when most others wouldn't.  Baseball though?  That's the epitomy of boring..as Paul Tagliabue said best, "Baseball is about as entertaining as standing in line at the grocery store." 

I play them for different reasons, depending on the situation.

1. They're pretty much THE social thing to do now when you're with friends staying in. I mean, Halo or SSBB or Mario Kart--these fun social games are always a conduit for a good time with a few buddies.

2. Sometimes I need an escape from the real world. That's when I'll pop in a non-realistic game like Mass Effect, Animal Crossing, Spore, or Mario. They take the stress off and put me in a completely different headspace.

3. Sometimes I just want to shoot stuff

Apart from the entertainment value, fond memories is the main reason why I still play videogames.  Back in the 80s and 90s I used to play videogames with my friends. It was more of a social thing. These days I play PC games online. As you get older, two player, switching turns and split screen isn't what it used to be. The games were much more difficult and I got that feeling of accomplishing something when playing through all the games. These days difficult games are nonexistent. Also...hanging out in the arcades was fun. Yeah, that's pretty much it. Nostalgia, entertainment value and habit.

Haha stress reliever. Way to escape problems and issues and dive into another world. Really the main reason I play it. Just to take my mind off the real world. Escape per se. Now I do also play it as a hobby and view it as an art but that's what it's mainly there for, for me.

chilling out i suppose

To keep me from playing Maple Story.

they are AWESOME!!!

......and i played them since i was 3 yo!

for fun

to relax

to challenge myself

I do it for entertainment.

Also gaming is a great social hobby, beleive it or not. Going to a held gaming event like tournys and such you can find many intresting people who like gaming just as much as you do ^-^