SugarCube's Insomniac Asylum

Personally, I find that writing itself brings the inspiration. That is, if you can make yourself write even when not inspired, something will come to you.

What I find useful in that regard is what I call a "core dump" (because I'm a UNIX geek from 'way back). I've heard it called other things, like "freewrite." Just take your preferred medium - I open a blank Word doc, but a pen and paper will do as well - and start writing whatever comes to mind. No need to edit yourself because no one else will ever see it (one hopes). Some people set a timer. I just shoot for filling up a single page. You can do more if you like.

You might get some good ideas this way; if so, you can incorporate them into whatever actual project you're working on.

It usually works for me, but everyone's different.