When Two Stories Call

In two days I enter the writing portion of my summer: three and a half uninterrupted weeks when both of my kids are at camp.

I can't wait!

My only problem? TWO works in progress can't wait either. Every time I sit down to start planning one, the other's voice gets stronger. If I switch, the same thing happens in reverse.

So what am I to do? Work on both? One in the morning and one in the afternoon? Lock one up until the other one is finished? But how do I decide?

What do you do when more than one story calls to you?