Beer at Work

I need some help from all of my KC brew buddies. Recommendations, anyone?

We have a kegerator at work, and it is currently empty. It is empty because we can't seem to find a decent source of small/pony kegs. When we have giant parties, we go thru standard sized kegs, no problem. But our office staff of 9 can't seem to kill a keg in a timely manner, and the lines get gross, and by then, well, it's just too late. We all like interesting beer, and variety. We have good beer in the fridge, but it just seems like a waste to have a kegerator and not use it.

So, where can we pick up pony kegs of GOOD beer? (Don't tell me to brew my own. I know. I'm just starting to get my head wrapped around that, and you really wouldn't want to subject my coworkers to a first batch.)