Here's a fun activity for Valentine's Day- Origami Hearts.
I found a great tutorial on how to make them here.
I made all these hearts a couple of years ago and turned it into a garland for fun holiday decor. This would be a fun activity for the whole family. It is cheap, easy, and pretty quick once you get the hang of it. I got a whole stack of pastel paper so mine would look like conversation hearts, but you could do brighter colors for a bolder look.