Unscrew strategic light bulbs so that they won't switch on. Shortsheet the bed.
Fake bugs are good, in the cup by the sink, etc.
Draw a chalk outline right outside your apartment, with yellow tape stretched over the front door. Bang against the door for a little dramatic flare. Be creative with voice mails, emails, and memos. Invent new company policies involving mandatory nudity, sexual awareness seminars, etc. Then laugh and laugh.