Here is Mr. L.'s Kalamansi Vodka Tonic recipe. I think they are wonderful, especially on a hot day.
1½ oz. Vodka
1 Kalamansi, halved & seeded
Fill a highball glass with ice. Add 1½ oz. Vodka. Top with Tonic water. Stir gently. Squeeze seeded Kalamansi over drink, and float halves in drink.