Chicago Dining- Lettuce Entertain You

As a wedding gift, my husband and I received a $50 Lettuce Entertain You gift card (Chicago-chain). We're kind of new to the city and could use some advice on the best use of this card. We'd like the best meal possible without adding any of our own money. We're especially interested in the L20 lounge (not tasting menu), but the prices are not online.) Thanks!