The desk drawers typically feature a selection of paper clips in all colors, sizes and shapes together with various other supply like colorful textmarkers, tippex, post-its, and undefined sticky substances. The first desk I got in a department of physics was passed on to be my by the previous only-women-at-the-institute. She nicely left some tampons. When I arrived at PI my desk drawer unit was full with my new office mate's files. It took me several months to convince him I really do need some space myself. (Nice girls don't only not get the corner office, they don't even get a desk drawer.) Looking into the bookshelf next to my desk, it was filled with notes and papers and folders and business cards from pre- and pre-decessors.
I changed office during my second year at PI due to an incurable disagreement with my officemate about what constitutes a life-friendly room temperature. This degraded me down to the 2nd floor where the view isn't so pretty, but also upgraded me to a window desk. While there was still plenty of space for my few things in the shelf, that office too already featured some folders and files of unknown origin, some filled, some empty. I also found a copy of Weinberg's first QFT volume that I happily used. It doesn't have any library stickers on it, and I have no clue whose it is. I'll leave it for whoever gets the desk next.
It is also always interesting what's under the keyboard or to check if there are sticky notes in the drawers. They will typically feature phone numbers, email addresses, or cryptic combinations of numbers and digits that probably are some of the dreaded random-generated keywords the insufficient human memory is sometimes forced to deal with.
And PI isn't even yet 10 years old! In the advanced stages, it will look like the ITP in Frankfurt did. Upon being shown your new desk, you realized all bookshelves were full already with books, papers, files and notes that had accumulated over decades and that nobody ever dared to throw out. After all, they belong to somebody, right? Offprints and proceedings seem to be particularly vulnerable to abandonment. The walls will be covered with helpful notes, like "if the phone doesn't work push the plug," or "if AC runs havoc call XYZ & chatter with your teeth."
And let's not even talk about hygiene. Shortly after I changed offices I accidentally spilled coffee on the floor. A full year later, the spills where still there. Acting out on a severe case of PMS I asked what the cleaning staff is actually payed for. Next day, the coffee spills where gone, but the floor is still covered with dead insects and spider webs in the corners. The occasional pencil stroke on the desk is also preserved for future generations. A study by the University of Arizona found the typical desk has hundreds of times more bacteria per square inch than an office toilet seat.
It's also amazing what people store in their offices. One prof I knew used to dry his bathing trunks in his office. Many have various sports equipment and clothes, towels, and shoes. I've also come across shaving supply, suitcases, plumber's helpers, silver- and dishware, condomes, ropes, empty pizza-boxes and leftover food in advanced stages of decay, plush toys, action figures, pillows, pet food, jumper cables, and toys, tools and technical equipment of all sorts. Somebody should make a movie about physicists being trapped in their institute, needing to come up with some ingenious construction to save their lives from what's to be found in their offices only.
I'm looking forward to my next desk :-)