1. That Which Invalidates Fasting And Requires The Day To Be Made Up

a. Intentional eating or drinking

As for the one who does it out of forgetfulness, then he/she does not have to make up for that day later according to this hadeeth of hurairah (R );
The Prophet (PBUH) said: “Whoever forgets he is fasting, and he eats or drinks, is to complete his fast as it was Allah who fed him and gave him something to drink”
(The Group-Bukhari, Muslim, Tirmidhi, Abu Daud, ibn Majah, Annasaaee)

b. Intentional vomiting

If one is overcome and vomits unintentionally, he/she doe not have to make up for that day according to a hadeeth bu Abu Hurairah (R ) that the Prophet (PBUH) said: “Who ervr is overcome and vomits is not to make up for the day.Whoever, vomits intentionally must make up day.” (Ahmad, Abu Daud, attirmidhi, ibn Majah, ibn hibbaan, addaraqutni, and alhakim who declare it saheeh – authentic)

c. Menses and Post Natal Bleeding

Even if such bleeding occurs before the sunset. There is an ijmaa’(consensus of scholars) on this issues.

d. Ejaculation of sperm (non sexual intercourse)

This could be due to kissing, hugging, etc. As for the wet dream, it does not void the fast.