Explanation Anyone?

My question for the day: Can anyone explain to me why toddlers think it's a great idea to change their schedules?

Further explanation behind the question: For roughly the past week to week and a half Luke has decided he doesn't much like his bedtime (usually between 8 and 8:30). Rather than quietly going to sleep like he used to do, now he explores his room, finds very random things to play with, talks and sings to himself, reads stories and open and closes his door to yell at us from the gate. This is all fine and good for a few minutes but the last couple of nights he has stayed awake until 10 doing all this stuff! I suppose that is okay too but I'm not very much in favor of him staying up that late and sleeping in until 9ish and then not wanting to go down for his nap until 2. I know I could break the cycle (hopefully with MDO today it will) but I really don't like the idea of having a super cranky toddler for a day while we maybe get his schedule back to normal. Sigh! Oh the life of a 2 1/2 year old :)