The Shamrock Shuffle is such a fun race that everyone should experience at least once. There is a lot of enthusiasm, Chicago loves St. Patrick's Day, and everyone goes all out, wearing their best green attire. This race follows part of the same route as the Chicago Marathon, so you get a small taste of what that race will be like too. Parking isn't great but if you take transit, it's a breeze.
The after party is a blast and overall, it's one of the best spring races in the area.

The Phoenix Rock'n'Roll half marathon is a ton of fun and a great way to view the red rock scenery in Tempe. This race does not really go through Phoenix proper, in case anyone is looking for that experience. However, the scenery is beautiful, especially in January.
I felt there could have been a couple more aid stations on course and at the time, parking was a bit lacking, but that could be better now. Overall, it was a great race and a fun time!