Amazingly, we've never done "nerds." Or "really really big." Or "really really small."
Here's one that might pose an interesting challenge: avatars where you can tell what the line of dialogue is, without needing to hear it. Or open it up, to any avatar that you can look at and "hear" either what is being said, the music that is being played, sound effects, etc.
Another challenge: What happens next. Avatars where you can look at them and know exactly what's going to happen next.
Here's one that might pose an interesting challenge: avatars where you can tell what the line of dialogue is, without needing to hear it. Or open it up, to any avatar that you can look at and "hear" either what is being said, the music that is being played, sound effects, etc.
Another challenge: What happens next. Avatars where you can look at them and know exactly what's going to happen next.