As much as I hate forms, I have to find ways to "spice" them up. I have come across some good ones and some not so good ones. I sometimes like the agonizingly slow tempo, and often do hand only stuff when I'm at work.
Heres a couple I do like.
Try isolating sides, ie left arm and foot techniques only..
Or do the whole thing in reverse.
Have a partner, and alternate techniques and sections of the form
If you're a real glutton for punishment, try mirroring the form. (a turn left, right punch becomes turn turn right left punch.) its insidious. ( a secret, it also helps train the techniques from both sides...)
Or, take it completely out of context. Start with one form, then work to a point where your stance/posture is the same as a different form, and continue with the new form, and try to switch back to the original at some point...
Like I said, I hate doing them, its like going to the hospital for me. I'll put it off as long as possible. but when i do go, I have to find some way to ease the suffering.
