Tonight is Wonnenacht, more commonly known as Walpurgisnacht. It represents the end of the Wild Hunt, the end of the Dark Half of the year, and the return of Holle to this realm.
With some differences among faiths (Holle vs. Walburga, for example), Braucherei and Urglaawe traditions state that tonight the Hunt passes through the homes with Holle (syncretics and even some Christians identify this with Holle) doing Her inspections for order. As such hallways should be clear of debris. Spring cleaning should be completed. Signs welcoming Holle (or Walburga) are to be placed on the doors and windows of the house, and as many doors and windows are to be left open as is safe overnight (screens are fine).