1.   All at once an idea popped into her head.

2.   As Kamm explains it today, an idea popped into his head as he was sitting there.

3.   His ideas popping half-baked into televised musings, the House speaker is a flailing barroom brawler, all windmills and roundhouses.

4.   It was the last stop on the tour, we were in Des Moines and the idea popped into my head.

5.   One day, an idea popped into his head, as ideas constantly do.

6.   Too many random funny ideas pop into my head, and I want to do them all.

7.   Which is not to say that novel ideas pop out of nowhere.