Gone Reading, the philanthropic book product site, is having a giveaway in May - which they're calling the Month of Mom. The prize is $100 to use on the Gone Reading site and a $25 gift card for Amazon.
There is a rafflecopter entry form, as well as suggestions for Mother's Day gifts. You can enter several times for liking them on facebook and following them on twitter, pinterest, etc. It doesn't say who's eligible to win (but I assume it's US + wherever they ship to *).
*Which according to an email I received (and now written on their giveaway post) is: the US, Canada, UK and Australia.