New Scientist 13 things that do not make sense - Features. Here's the 13 things, read the article to learn the details (and perhaps cause your head to spin a few times):

1. The placebo effect
2. The horizon problem
3. Ultra-energetic cosmic rays
4. Belfast homeopathy results
5. Dark matter
6. Viking's methane
7. Tetraneutrons
8. The Pioneer anomaly
9. Dark energy
10. The Kuiper cliff
11. The Wow signal
12. Not-so-constant constants
13. Cold fusion