I was really nervous about this, too. I told my doctor I was going to disconnect from my pump for most of prom and just give an occasional bolus to sort of pose as "basal rates" -- which isn't really the best solution.

Instead, she suggested I take an injection of long-acting insulin for either half the day or for the entire day, and then use my pump for blousing for food (or I could take shots of a short-acting instead, too). I ended up deciding to disconnect from my pump completely and took an entire day's worth of long-acting insulin (for me, that's 25 units-the total of my basal rate amount of one day). I didn't want the infusion site to show through the material of my dress, so I carried my short-acting insulin with syringes in my purse (my glucose meter!) and took injections when I needed to.

It worked out really well and I didn't have any problems.

Ask your endocrinologist to help you figure out the different dosage amounts and try to check your blood sugar frequently that day, because long-acting insulin isn't a perfect match to the basal rates you're getting from your pump. And have fun!!!