Ubuntu 9.04, because of WUBI (anyone remember that?). Unstable as hell, but allowed you to run a near bare metal Linux install without the hassle of setting up dual-booting and a separate partition. Liked Ubuntu it so much that I soon replaced Windows completely. Currently running Debian, so I haven’t strayed far from the family.
I’m assuming open houses aren’t a thing in Belgium? In the US, it’s no big deal to walk in to an open house and just tell the agent that you live in the neighborhood, like the house and have always wanted to see the inside. They’re usually pretty chill about that.