Students are divided in groups. Each group gets an envelope  with 4-5 adverbs of frequency written on slips of paper – e.g.  ALWAYS, EVERY YEAR, NEVER, SOMETIMES, TWICE A DAY, EVERY  DAY, ONCE A WEEK etc. The task is to make any kind of sentence by using those adverbs. E.g. if you give 4 adverbs to your students they'll have  to write 4 sentences. When the students are done writing, they come to the whiteboard and copy the sentences they've come up with. We read and discuss the sentences together and correct any potential errors.