Unfortunately, You Should Probably Quit Normally
After all that, the genuinely sensible option sounds painfully uneventful. Speak to your manager privately, explain that you've decided to leave, give the correct notice and confirm everything in writing. Work your notice properly, leave a decent handover and try not to create a story that follows you around for the rest of your career. If you're genuinely planning to leave rather than imagining what you'd like to do after a particularly difficult Monday, we've also written a proper guide on how to quit your job without making it weird.
Careers have an annoying habit of bringing people back into your life. Former colleagues become managers, managers move to different businesses and somebody you worked alongside five years ago can suddenly appear across the table during an interview. A ridiculous resignation might give you an excellent story for the pub, but leaving properly gives you something considerably more useful: people who would happily work with you again.
Once you've escaped without cakes, treasure hunts or abandoning anybody's lunch, you can start thinking about what comes next. Get your CV sorted, prepare properly for interviews and start exploring current vacancies without detonating your existing career on the way out. Leaving your job doesn't need to be memorable. Ideally, the exciting part should be where you're going next.
Although we're still willing to hear arguments in favour of the cake.