1. Poisoned wine.
2. Very large pit trap located in room, an illusion of a nice warm bed is in its place..
3. A rather pissed off ex lover with a large club.
4. Dragon needs a bouquet of dead heroes for his girlfriend.
5. Love letter (with curse written in magic).
6. Death by chocolate. A vat of 100 gallons of smoking hot chocolate pours from the ceiling.
Happy Valentine's Day.
*I may add a few more later.