I use various live wallpapers, they don't slow down my phone at all.
Just let her play with an iDevice so she can see what "boring" really is. She'll be begging to play with the Nexus.
"Remember, friends don't let friends use IOS"
Change your launcher to Go Launcher. Add Pwall its a wallpaper changer you can set to change and pull wallpapers from specific folders at times you specify. That should help ease the boredom.