Very simple and lame passwords:
1) 123
1234
123456 and so on depending on how many digits are required by the service.
2) qwerty
3) admin
4) 7777777 (seven sevens - for some reason people like it)
5) your birthday digits, because it's very easy to guess them from Facebook, MySpace and other social networks
e.g. May, 11th - 0511
6) god, sex, love as it was in a movie
7) words "password" or "pass"
8) xxx
9) your home or cell phone number (digits are easily accessible from social networks)
10) your favorite color, plant and so on like "pink", "rose", "lilly"