Requires

Magistrate's Scepter must be on the battlefield. Energy Chamber must be on the battlefield. Tawnos, Urza's Apprentice must be on the battlefield. Magistrate's Scepter has three charge counters on it. Mana needed: each turn

Steps

1. Activate Magistrate's Scepter, removing 3 charge counters to take an extra turn.
2. Activate Tawnos, copying the extra turn ability.
3. Pass the turn.
4. At the beginning of your upkeep, Energy Chamber triggers, putting a charge counter on Magistrate's Scepter.
5. Activate Magistrate's Scepter, putting a charge counter on itself.
6. Activate Tawnos, copying the trigger.
7. Pass the turn.
8. Repeat.

Results