Good luck, edenluna! Before bed tonight I'm definitely sticking one of the big chux pads between the mattress and sheet. We just bought this mattress a few months ago and dp would positively kill me if my water broke on it!
Last night we stayed up way too late watching TV, and I was having pretty strong contractions the whole time. We went to bed at about 2am, and they were still coming, but I was able to fall asleep anyway. Then at about 6am I woke up having very intense, very uncomfortable contractions with back pain every few minutes - I was really beginning to think this was it! Ctxs have never actually woken me up before. But then they stopped.

: I'm still having quite a few strong ones today, and I was nauseous all morning, and my lower back is bothering me (ooh, here's another good one...)
I'm thinking definitely this week. My friend guessed Thursday, and she correctly guessed DS's birthday (and exact weight, coincidentally) so we'll see if she's right again. If she is, our babes will be 2 weeks apart - our toddlers are 2 months apart, which is fun because they've pretty much always known each other.