I love Joanne's linky party. There are so many positive ideas...one of these days when I have free time I need to go back and read them all again so I can actually get started on incorporating them!
But for now I have a very simple motivator to share - the Staple's easy button.
I've had this for years. It was just an impulse buy in the store one day. Basically I keep it by my guided reading table and use it when I am working with small groups and individuals. It's amazing what they'll do to press the button (which says "That was easy!").
I've been calling kids to my table all week to assess high frequency words, do a quick phonics screen, etc. When they are finished, I let them press the button. All the other kids look over and actually get excited when they get called over...the first thing they say is "Do I get to press the easy button?" And then when they are finished, if I don't say anything, they sort of just look at me and the button until I realize I forgot to tell them they could press it.
I also use it during groups if I am asking for answers....like make a connection or find a text feature, fact, etc. If they can, they press the button. All of a sudden everyone else in the group can come up with something too!