Sanctum Weaver and Aggravated Assault on the battlefield.
You control at least five enchantments.
Sanctum Weaver does not have summoning sickness.
Steps
Activate Sanctum Weaver by tapping it, adding at least ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Activate Aggravated Assault by paying ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) , untapping all creatures you control and causing you to get an additional combat and main phase after this one.
Repeat.
If you control six or more enchantments and/or control another creature that can tap to produce mana, this combo nets infinite mana.