We were eating dinner with my parents last week and Sam said "Look, Mommy." I glance over and stop in disbelief as I see Sam stick a pea up his nose. While he has been experimenting with sticking his finger up his nose in recent months, it's never occurred to him that other things could fit in there. I had a look of shock on my face and exclaimed "No, Sam, that doesn't belong there" so Sam immediately started to stick his finger up his nose to fish it out. Luckily I was able to stop him before he shoved it up further and was able to get it out myself. Later that week he fished out a booger from his nose and tried to eat it (first time for this too!). Welcome to raising boys...
Dec 09 update: I think I am losing the battle of preventing Sam from picking his nose. I knew I was particularly doomed the other day when we were visiting friends and he picked his nose and tried to hand it to me. I said that was gross, I didn't want it and he said "No, Mommy, it's for you to eat." Sigh.