+1 for triathlon. I love the variety - my swimming is cr*p, my cycling is worse, but my running is OK. I do it for fun. And I get to wear lots of rubber and lycra, and buy loads of stuff I don't really need.
My running is a bit more serious, but I do intend to try and inject a bit more fun into it.
And Loch Ness is going to be fun. I have heard of folk getting PBs there KS, so don't be put off by the profile.