As willpowered says, watching other gamedevs is sometimes enough to do the trick. What works for me is listening to a programming podcast or reading a book about game development (or just programming in general).
Current recommendations in podcasts: TechZing, Walled Garden Weekly;
Books: David Kushner's Master of Doom, Randall Stross's The Launch Pad.
Wow guys, thank you all for your great advices. I've already bookmarked the podcasts, books and whatever you guys have suggested.
I immediately watched Indie Game: The Movie, and I can say that; there is my god damn motivation. Thank you all.
Sometimes the best thing to do is to just play a game you love. I find it really inspiring and motivating seeing another developers work that I admire, often after playing a game I enjoy it makes me want to create my own even more.
