When I get bored with riding mucho miles on my road bike, I hit the trails instead. It's also cooler in the woods than it is on the road. And it's so much fun that I'm reminded why I love cycling to begin with! Just yesterday, I hit some sand and went flying off the bike landing on my shoulder. And then I just started laughing! (Thank God no one was around.) Mountain iking just helps me take my riding less seriously.
I also joined up with a group last Sunday to try a new (road) route, even though it took me 35 minutes to drive to the location. The new scenery (and camraderie) made the ride much more enjoyable. Mix it up!!