I had a couple number lines that I bought when I first started teaching. I only used them that first year, but I just couldn't part with them. I don't know why... I think it's because they were among the very first things I bought for my classroom.
I decided that I had to either use them or lose them. I ended up cutting them up to create number "puzzles" for math centers. I like them in the beginning of the year for a little extra exposure to two-digit numbers.
I just have the students put the numbers in order and record it on a recording sheet. Since I had two number lines, I did one set with consecutive numbers (20-21-22..) and another set with random numbers (12-29-37...), but the objective is the same.
I know this isn't ground-breaking or particularly special, but I know a lot of us have random things lying around our classroom, so here's a way to make use of some of the junk. :)
Here is a link to the recording sheet I use, in case you are interested.
xo, Ally