I have the urge to write, but lack the idea of what to write about. Any suggestions?

Maybe bạn could pick a book that bạn like and write a fanfiction that takes place before the book began, to explain something that the book didn't explain. I've been thinking about doing that, but I've never written a fanfiction and I feel like it would be weird...

When I do some writing, I usually do either:
1. A mystery story.
2. Stories about my dogs. I find that pets give me a lot of funny items to write about.

bạn can write A to Z

then

1-100

then Roman Number
from 1-50

after all this if still bạn have any energy left then
write an Easy on Cow ---Mooooowwwww mOOOOOOOO !!!!

I don't haven any ideas in particular but when I feel low on ideas I usually go onto Google and tìm kiếm up 'fantasy' and then make a story based on one of the images. Usually works as a good warm up.
hoặc I write a story based on a song.

Just look around bạn and see if there's anything that would give bạn inspiration. That's what I've done before. It's helped me out with my story that I have on my Google Docs that's 130 pages long, lol!!XD

But just see if bạn can get any inspiration from any everyday things that bạn see everyday. Either that, hoặc things that have happened to bạn in the past that's worthy of a story.

Write it about me :D

The best way I come up with stories when I'm stuck is to take an event from my life, then expand on it. bạn can make this event so outlandishly exaggerated and add fantaisie to it, hoặc keep it pretty true to the source, and it'll be easy to write because bạn have personal experience about the basis of the event itself.
Works every time :P