if you can find it near you, you might like Brezza di Mare from Il Profumo di Firenze (i think it's iPdF anyway)... it has this very nice and refreshing watermelon note in the base. I thought I would hate anything with watermelon as a note, but I love this stuff. Very light, refreshing, and summer-centric.
Another thought might be Story from Paul Smith. I guess technically it's ivy notes over verbena notes, but on me it's got a bunch of great citrusy notes and the topnotes and midnotes are redolent of grapefruit.