Grind 2 tsp each coriander seed and fennel seed with 3/4 tsp crushed red pepper with a mortar and pestle (or spice grinder). Add 3/4 tsp garlic powder and 1/2 tsp kosher salt. Rub boneless, skinless chicken breasts with mixture, let sit 30 minutes, grill or broil.

Here's a rub that's great on pork, might be good on chicken too.

2 TBS chili powder
2 tsp cumin
1 tsp granulated garlic
1/2 tsp paprika
1/4 tsp granulated onion
2 tsp salt
1 tsp pepper