Absolutely. Sometimes it happens when I'm debugging something and I get stuck, other times it happens during the design phase, when I'm trying to figure out data structures, etc. I find out that walking away is more efficient than sticking with it in many cases. Sometimes the answer comes to me on the ride home, or while I'm mountain biking, or mowing the lawn... then the trick is to remember the solution. I send myself emails, leave myself voice mails, or write the dreaded yellow sticky notes before that part of my brain is overwritten.