I posted earlier how I was using exit slips in class now (in my general level Alg1). The kids just accept it as something they need to do and I don't give them their assignment until they've turned in their slip.
I have three bins out for the kids to turn their work into; a green, a yellow, and a red (see this post). I ask them to put their paper in green if they're confident in the answers, yellow if they're not sure, and red if they have no clue. Several people have asked me if the kids actually do this (or if there's a "stigma" attached to the yellow/red) and I'm happy to report that they do! That doesn't always mean that the green results are good or the yellow/red are bad, but it's about the kids' confidence level with the material.
The great thing is that I use my exit slips to help focus attention on the kids who I know need it. Tomorrow I'll be sure to reassure student #1 that she's doing great and sit with student #2 to work through more problems.
I don't return the papers to the kids and have seen the idea of creating a laminated exit slip to use over and over again... I may go this route if I can be sure the markers (or whiteboard crayons, since I have some) will erase easily.
And for a REAL #Made4Math: I'm pretty darn proud of this google site that I set up for my precalc kids to do some fractal explorations. I showed them some of the PBS Nova video in class on Friday and they were disappointed that we didn't have time to watch it all!