Here's an idea for an afghan:
Cast on anything with a multiple of 10: 70, 80, 90, etc.....
Row 1: K10, P10 across
Row 2: Knit the Knits and Purl the Purls
Do this for 10 rows THEN:
Row 11: Purl 10, K10 across
Row 12: Knit the Knits and Purl the Purls
Alternate the blocks until the desired length.
Something else to think about!