Another great link:

I always enjoy reading the what’s on sections of magazines: but they give you too little time to plan.
Here’s the solution:

whatsonwhen.com “is dedicated to providing high-quality travel and entertainment content solutions.”

It even includes video impressions of recurring events such as festivals and helps you to plan your activities through a personalized calendar.

Great stuff!
Tip for Dutch readers: Nationaal Museum Weekend (10+11 april)