Past Tense Minefield
Don't step on the regular verbs as you walk through the minefield.
Move your mouse,
over a minefield made up of verbs having regular and irregular past tense forms. Step
only on the verbs having irregular past tense forms,
or you're dead. The regular verbs are the obstacles for a change.
Past Tense Minefield (with occasional earth tremors)
Same as above, except that minefield is now in an earthquake zone, so you have to be extra careful because of occasional earth tremors.
Past Tense Minefield (with timer).
A much more challenging version of above, since you have to beat the clock.