Preheat a grill. Place the shrimp on skewers and season with salt, pepper, and fresh thyme. Place the shrimp skewers on a platter, drizzle with olive oil, and let marinate for approximately 20 minutes. Place shrimp skewers on grill and cook for about 4 minutes per side.
Peel and mash the avocados with a fork, making sure you leave it a bit chunky. Chop the garlic and cilantro. Add the sour cream, garlic, and cilantro to the crushed avocados. Season with salt and pepper, and add the lemon juice.
To serve, place a spoonful of the guacamole on a plate. Place the shrimp skewers on top of the guacamole, and garnish with grapefruit supremes.
Recipe courtesy of Josh Eden, Ocean Club, Nassau, Bahamas