I am a non-bookmark kind of reader. I have tried in the past to like bookmarks. I have been given many, many, many bookmarks over the course of my life, but truly, I don't use them. They get lost or put away somewhere so they are never handy for when I need them. I'm a fold the page down to mark my place kind of reader. I also use the tried and true 'let the book rest upside down to the page I'm at' technique. I do have 2 exceptions to this rule, and they are both for my Bible reading. My regular size study Bible has a ribbon attached to it that I will use to mark my place, or a passage that I want to come back to. I like the ribbon because it never gets lost, it's right on the book. The 2nd Bible is my pocket thin NIV that I bought specifically to carry to work or wherever the day takes me. I specifically went out and bought a magnet bookmark for this. Again, this bookmark never gets lost because it attaches via the magnet. Because the Bible is a book I read again and again I never put that bookmark anywhere else. Other books I spend a couple of days on and then I'm onto the next read so a bookmark wouldn't make sense for me for them.
As for odd bookmarks? Hmmm, the one that comes to mind wasn't for a reading book, but rather my dayplanner for work, I stuffed a CD in this week to mark my spot, a first for me.