Experiments for a Sparkly Science Party

The party is coming up in less than two weeks, and I STILL have not settled on the experiments we will do!  The internet can be too much of a good thing, I keep finding great ideas and options!  Here's what I have so far:

1.) Sparkly Explosions.  I definitely want to do the vinegar and baking soda experiment.  We've never done it for Serenity before, and she'll especially love it if we give her the option of personalizing it with a little glitter and food coloring!  I expect a lot of pink and purple volcanoes from her =)  We've playtested this one so we know exactly what we will need to have on hand, which is basically a giant bag of baking soda, gallons of vinegar, food coloring and glitter.  Plus I plan to have clean soda bottles for each child to make their own, and possibly trays to contain some of the spills.  Supply wise I also got some plastic squirt bottles to make it easier to get the vinegar in the bottles, funnels, and beakers.  I know we need a lot of vinegar because when we play-tested it I kept pouring more and more vinegar into mine, it was such fun!

2.) Glitter Jars.  This will be a fun take home for all the kids, with the benefit of a little science.  I still need to test and figure out which method is best.  The one I'm leaning toward uses distilled water and glycerin, plus glitter and sequins to make the glitter jar.  The science part is that the glycerine is denser than water so it slows down the glitter and makes it settle slower.  From the pictures I've seen, this may be quicker to settle than the other option. 

The other recipe I've found involves glue, or possibly glitter glue and food coloring.  I love the look of these bottles, but you need warm water to melt the glue and I'm not sure how easy that will be to work when I'm making 13 or so bottles with kids ages 3 and up.  Hence the play testing.  I do have funnels for getting the glitter in the bottles, and maybe I'll get little tongs or tweezers to transfer sequins.  Everyone can personalize this with their own color, glitter, and sequin choices.  I also need to hot glue the lids shut or duct tape them.

3.) Mentos and Diet Coke.  I immediately thought of this when we decided on the science party, but then I worried it would make a huge mess in my yard.  But I saw pictures of one family that managed to do it in their driveway without even getting slime on their car so I'm going to go for it.  Now, I just want to find out if this will work with diet Cherry 7-up, because neon pink geysers are perfect for our Sparkly Science Party!

Other possibilities I'm still considering:
4.) Homemade Gak.  With glitter.  Possibly just as a favor instead of an experiment.
5.) Marker Chromatography.  Serenity's Grandma actually does Chromatography experiments for her real job, so this would be really cool!  If it works.
6.) Peeling the S off a skittle. Fun!
7.) Balloon Rockets