It’s easy to forget what is fun in a game, and in this case Diablo3 .
Often times people get so caught up in progression it turns into a job, and becomes a repetitive chore to just play. So here are my suggestion to you when you are bored doing whatever it is that you are doing, which my guess would be farming Inferno, act 1, 2, and if you are lucky, 3.
1. If you are playing with your friends, or helping them level, buy some cheap legendaries, or good/bad yellows, and drop them on the ground when you kill a boss or elite champion pack. Keep doing this and they will probably start thinking they are the luckiest person in the world.
2. Play Hardcore mode! Hardcore mode in Diablo 3 is almost a different game, sorta. It adds more challenge, a purpose, there is no real money auction house, so the gold auction house is better and more stable, plus gold is worth more.
3. Farm for Achievements! This is probably one of the best things to do in my nerdy opinion. There are tons of fun things to conquer if you are going for achievement points. It will give new life to the game, at least until you finish all the easy/semi easy ones. This is the only thing that kept me playing World of Warcraft in my later days.
4. Make/LVL a new character to 60.
5. Try funny builds
6. If you are rich, buy a cheap gear set, lets say 500k or 1million max, and see how far you can progress in inferno with it