Slat, this is gonna sound kinda nuts but if you have any meditative practice or prayer practice it can be kind of cool to bring it to your cardio.
Nowadays I only need to get through the first 2 minutes or so before my brain tunes out but at other times I have used this technique.
Other things I do to bring some enjoyment to the whole experience:
- good tunes are paramount
- being willing to part with music all together and just enjoy the quiet when running outside somewhere nice
- running outdoors anywhere cool (trails or city blocks you've been meaning to check out)
- timing cardio with your favorite tv show and watching while getting 'er dun!
- playing "numbers games" with the time or speed, for example... Sprinting from 12:12 to 11:11, recovery jog until 10:10, sprint to 9:9... Etc. I usually put a machine on manual and mess with it myself. This keeps it interesting.
- engage your inner competitor... even on a treadmill at the gym find a "mark" and try to match his cadence
- do a spinning class, try swimming, play basketball or tennis. Anything that has you sucking wind is going to be training you in some way. It doesn't have to suck.
- jump rope
My plane is taking off... Gotta fly