Simple ideas:
Macro
Go to a museum — a natural history one, a museum with skeletons, or other animal/human material:
Photograph strangers
It is simple:
Go outside, walk around, and photograph strangers you find interesting to you!
Chicago dancing man. Canon 5D and 17mm 
Shoot your selfie
The best person to photograph is yourself!
The color red
I love red. Why? It is the color of blood, passion, danger. The color red puts wind into my sails!
Gas stations
Gas stations — currently a mainstay, but perhaps will eventually be made redundant with electric cars, etc.
Thus, perhaps right now it is a good opportunity to pursue a photography project of gas stations! These will one day become a relic of the past.