Flash + Protean Hulk + Ezuri, Claw of Progress + Sage of Hours + Dryad Arbor + Ornithopter + Memnite + Phyrexian Walker

Flash

Protean Hulk

Ezuri, Claw of Progress

Sage of Hours

Dryad Arbor

Ornithopter

Memnite

Phyrexian Walker

How it works

1. Cast Flash putting Protean Hulk into play, choosing not to pay.
2. Sacrifice Hulk, getting Ezuri, Sage of Hours, and 4 0 mana value creatures.
3. Sage of Hours and the 4 creatures will trigger Ezuri's ability, netting you 5 experience counters.
4. Move to combat, triggering Ezuri's ability.
5. Put 5 +1/+1 counters from Sage of Hours.
6. Activate Sage of Hours' ability, removing all 5 counters, giving you an extra turn.
7. Repeat steps 4 and 5 for infinite turns.