I have an iPhone. Lots of my friends own one as well. Everyone who doesn't have one, bought a Blackberry, Droid, Treo, etc. What's my point ? Gamer or not, almost everyone has video games right at their finger tips at all times.
For the longest time, the only games you could get looked 4-bit. But now the games look amazing on practically ever mobile device ! There was also period of time where you could choose from maybe 10 to 20 games. But now almost every phone service and individual phone model has hundreds of options if not thousands.
There are a lot of good games out there and for a pretty cheap price. I think that Tetris for five bucks is a great deal. I am also admittedly a total whore for Yahtzee and that was only three dollars ! When I'm waiting in a doctor's office for an hour, I would pay way more than five dollars for something to do. Games on my cell phone are the perfect solution. There are tons of entertaining apps for the non-gamers, but whats even cooler is that they are now catering to the hardcore gamer. I had an app on my iPhone that linked my Call of Duty to my phone. I kept track of challenges, scores, etc. There are also ways to keep track of XBL, PSN, and Wii friends through different apps as well.
One of the few drawbacks would be that there are some really crappy games out there. I try to read the reviews but people's opinions are so varied. One person says an app is their absolute favorite and the next person will claim to hate it. When reading the review, look for specifics. See how many levels are in the game or if it links up to other medias. Especially if you aren't a regular gamer, you might want to look for a settings level that will allow you to start as a beginner or is easy to learn. Also be wary of apps that look like games but are not games at all. There are apps that do things like make your phone look like a snow globe, make farting sounds, or falsely empty a beer. They are cute the first couple times but that's about it.
So don't be afraid to venture forward into the world of truly mobile gaming. We all spend a lot of time in waiting rooms or in transit, a good boss fight might be exactly what you need to speed through those stressful minutes.