Dua before sleeping — Subhanallah, Alhamdulillah, Allahu Akbar
سُبْـحانَ الله (ثلاثٌ وثلاثون) الحمدُ لله...
سُبْـحانَ الله (ثلاثٌ وثلاثون) الحمدُ لله (ثلاثٌ وثلاثون) اللهُ أكْـبر (أربعٌ وثلاثون)
Subhanal-lah (33 times), Alhamdu lillah (33 times), Allahu akbar (34 times)
Translation
How perfect Allah is (33 times), All praise is for Allah (33 times), Allah is the greatest (34 times).
When to recite
Recited when lying down to sleep. The Prophet said this is better than having a servant.
Source / Reference
Al-Bukhari 7/71, Muslim 4/2091