Last year I finally broke past my 10K threshold and ran a half marathon. I had such a good time that I decided to train for a marathon in the fall, and this year, I've heard a few more friends say they're planning their first half marathons, too. If you're among those looking to kick off the spring with a half or a relay, check out the Platte River Half Marathon and Exchange Relay on Sunday, April 11. The race is in its eighth year, and last year it was named "Best Half Marathon" by Colorado Runner Magazine. The course sounds fantastic. Runners will start in downtown Littleton (just off the light rail stop) and will connect with the Platte River Trail. The best parts? It's a fairly flat course (there's a net elevation drop of 120 feet, in fact), and there's only one uphill section. If you're looking for a little less mileage, sign up for the three-person relay. Two runners will take five-mile legs, and one will run a 3.1 mile leg. More good news: If you register before February 14, the half marathon costs just $40 and the relay $90.