Yeah do shit you want to learn about and hopefully profit from.
I was SOOO into javascript for a while so I made a game with it, which I found extremely interesting and kept me motivated. By the end of working on it I'd refactored the code multiple times as I learned better ways. It should be refactored if I work on it again because I was a nub when I made it. But it has a skill system, loot system, mining system, monster spawn system, buy/sell system, and I roughed out mechanics for dungeons and recall runestones in 100% javascript:
[ame="http://www.youtube.com/watch?v=_fLODEM_0ls"]lol javascript 2d game engine I made in notepad - YouTube[/ame]