You’ve been given a bonus room. Caveat: it is not a bathroom, kitchen or any needful thing...

Well, if it's my imagination room I'd want it to be something like the Room of Requirement in the Harry Potter books - where whenever I opened the door, the room would be exactly what I needed at the time: Either a reading nook with comfy chaise and tea already made the way I like it, or a beach with lapping waves and warm sun that turns to sunset and night with stars as I linger, or a path in the woods I could meander in for a while then stop and sit and listen and contemplate, or a dance club with good music and drinks where I could dance, laugh and have fun, or a spa room with a massage therapist, or a wine tasting room, or ... So many possibilities!