Sweet! I love Line Rider. It's extremely addicting. If you want to see some cool videos search for "Line Rider" on Youtube. There is also a very strange method to make perfectly straight lines that I learnt on some site. First you have to start a centimeter or so normally, but then what you do is Rightclick where the centimeter of line you already drew ends, then rightclick anywhere else on the screen, and then leftclick where you want your line to end(you have to drag a tiny bit during the leftclick)
Anyways using this method ive made some very cool tracks. My favorite had a HUGE jump, with a perfect backflip and landing, and then two loops. Jumps are the funnest things to do in my opinion.