Kick your simple syrup up a notch by infusing it with tea. Play around with different herbal and black teas and infusion times. To start, this should be a decent guide:

Combine equal parts water and sugar in a small saucepan. Add a tsp of loose tea (or a tea bag) for every 100ml water or so. Heat over medium-high heat. Gently bring to a boil and simmer for a few minutes. Let cool. Strain out leaves. Syrup will keep refrigerated in an air-tight container for a couple of months.