Recently, I did the Color Me Rad 5k, and it was a ton of fun. It was probably the least pressured, easiest 5k I ever did. Plus, my friends ran around looking like assorted Skittles. They gave us these color packs that had colored cornstarch, and the best part was, we could attack random strangers. All in good fun! You come out to the event in a white shirt, and the 5k is your art canvas. It reminded me of my days as a kid getting into all the messy finger paints. Your worries and and stress goes right out the window in perfect abandonment.
If you've never done a 5k before, this would be a great starting point. There is no pressure, and no time to finish in. It does get bottled-neck in the color zones. So, you can slow down and take a breather. I highly recommend doing this run with friends! We headed to the nearest California Pizza Kitchen afterwards, and the looks on the waitstaff was priceless. In fact, one of my friends went into the restroom, and a poor lady tried to give her money because she thought she was homeless, lol.
Oh yea, make sure you wash your face as soon as your done, this stuff likes to linger for a few days.
Oh.. man! :)