Low weight/high rep circuits with maybe 3 or 4 lifting exercises, plus a 3-minute wind down on the stationary bike can burn about 400 calories in 15-20 minutes.
Just focus on keeping up a nice steady pace so that your heart rate doesn't fall too low.
You'll definitely notice the difference physically pretty early on doing that.
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"the golden state bridge on Tay's back has a 67 year old scotch covered turd on it between the gates" - upside, circa Montard's Revenge