I would think that if you wanted a song to mix, you would want to leave your comfort zone and mix something besides what you normally do. You grow more as a AE that way.
I have a few songs that would give you a real challenge. The amps used were 10 and 25 watt practice amps. One mic was used on everything. The drum tracks were stereo tracks mixed by the drummer. The vocals are weak and pitchy.
Let me know if you want to do some serious turd polishing.
And I also have one that none of the tracks line up.