My idea of fun is certainly different from most people's! I love running and I love trail running the most. Getting muddy doesn't bother me. I also love lifting heavy weights and challenging my body at CrossFit. It's hard in the moment, but the reward at the end is a feeling of accomplishment. Of doing something difficult, wanting to quit, but not giving up.
I have been struggling with finding goals for myself this year. What's a runner to do but to pick a challenging race? I signed up for a trail half marathon, Run From the Taxman, in 3 weeks on a segment of the Ice Age Trail. I ran there last fall during the Mammoth Challenge, so I know what to expect. It's really hilly, so I know it won't be easy. I'm already feeling anxious, lol.
Oh, but that finish line feeling is everything. And that to me is fun!