I'm not sure if I ruined the fun by giving them tangible mice to play with as opposed to the imaginary ones....
My friend Andrea posted some little mice she and her daughter made on their blog (not posting a link unless she says it's okay!), and I knew I needed to make some. I made up the pattern.
As you can see, I was lazy and used white thread. And I never got the chance to attach their seed bead eyes and noses -- they got snatched up too quickly. Yellow mousie lost his tail very quickly and ended up with an orange yarn prosthetic. Blue mousie, too, now has a prosthetic yarn tail -- it's yellow.
I wasn't too lazy to create a pattern before sewing them up, though! I can post it if someone wants it... provided I can find it in the wake of sewing project destruction on my sewing table!
Update 10/26/09 -- Here's the pattern!
Basic instructions: There are no seam allowances included in this pattern. I simply whipstitched the edges together! I sewed a double strand of yarn through their backsides once, then braided it, to create their tails. I included an "adult mouse" pattern too (I just blew up the baby mice pattern), mostly because the pattern is so tiny and the page looked so bare! You can add seed beads for their eyes and noses.