A tower of your verbs
A verb from your stories stands as a tower of six floors, ich at the ground and sie/Sie at the top. Build it from the bottom up by tapping the form each person takes, with one form among them that’s never right („fahrst“). A wrong one bounces back; once the tower stands, each slip is corrected where it was made, with the rule beside it: a → ä in du and er, an -e- after -t and -d, sein and haben as their own. Each tower is a little faster than the one before, against your own best, and the verbs you slipped on lead the next round. Separable verbs keep their other part at the end: ich räume auf.
Where: In Games, from home. Free, and it keeps your streak.