I read an interesting thread on the NSTA biology listserv that suggested teaching mitosis with DNA structure/replication instead of with meiosis as it is usually paired.  The idea is that mitosis is asexual reproduction and thus conceptually separate from meiosis, which is the basis of sexual reproduction.  I'd chosen cloning as the context for teaching about mitosis, and my students had started a webquest using the Learn.Genetics Cloning module.  I collected them to gauge their progress, and ended up with three groups of those who were almost done, those about halfway, and those who had barely started.  I put a different stamp on the papers of those in each group, and this was how I divided the class.  (Amazingly, this was the first time I had tried grouping the class this way, and it made my giant class of 25--which doesn't seem that big until you consider I only have 24 seats--a lot more manageable.)

I set up three stations and gave them about 25 minutes at each one.

Station 1 - Finish the cloning webquest.
Station 2 - Online Onion Root Tips (also available in Spanish).  Students read about the 5 phases of mitosis and sort cells into the right phase to determine how much time is spent in each one.  I gave them an online quiz through Schoology at the end.  Our state assessment is very general about mitosis, but knowing the phases is important for understanding meiosis, which is in turn a conceptual underpinning of sexual reproduction and chromosomal inheritance.
Station 3 - Build a DNA Molecule on the computer, then using Twizzlers and colored marshmallows.  This was everyone's favorite, of course, and the takeaway was very simple: A with T, G with C. Make sure students refer to the base-pair letters rather than just the marshmallow colors.

Much cheaper than DNA modeling kits, and every student gets to have one.