I did this once, but only once. I watched the first one, decided to watch the next one. Before I knew it I watched all three movies and it was waaaay too late ^^
I've done a TLK marathon... too much actually. Just yesterday I did 3 marathons lol. Just celebration for TLK's 15th Anniversary of course. ^^ I always start with TLK, then TLK2:SP, then TLK1&1/2. I am thinking of doing another marathon tomorrow.
Wow, I feel guilty...I only watched TLK once yesterday, when people are doing all of these marathons. I actually did a TLK marathon a long time ago, but I got pretty darn tired afterwards.