The Long Crusade to Mastery 5
When the Mastery system was first introduced, I decided to try and get ALL champions to Mastery 5. 6 and 7 will come eventually, but the more immediate goal is 5.
My current progress looks like this.
http://i.imgur.com/28lw367.png
The supports got to Mastery 5 first, because I'm a support main. Eventually I'll have to branch out to other roles to continue the crusade. So far, most of the champions at Mastery 5 are a result of me playing them as a support and getting away with it, or at least thinking I can get away with it (and most of the time, yes). This has actually made me a lot better at the game, internalizing all the champion mechanics and forcing myself to understand them better.
My current Total Mastery is 240+2. It's been rough getting this far, and this is only the easy part. With all the champions that remain, all the champions that literally everyone else plays, champions I can't get away with as the support, I can only see anger and fury going forward.
But I will persevere.