Definitely agree with the alyssum and lobelia -- the alyssum reseeds even here in the north, and I love the blue shades lobelia comes in.
I forgot that you can make the snapdragon flowers open and close like that, I guess it's been a while since I've grown them! I like to amuse myself in the garden by having an unsuspecting visitor touch a ripe impatiens seed pod and watch their reaction when it pops open (hey, I live in the country and don't get out much!).
