Here you can find lots of interactive online activities:
Was or were, by Martina
Find more: to be exercises in English Exercises .org
WAS-WASN`t-WERE-WEREN`T, by Rosario
Regular o irregular verbs?
Irregular verbs game: GAME!
Past simple: biography
Past simple: -ed pronunciation and irregular verbs. Interactive English.
Is the following game familiar with you?
Click on the image to play the game.