Courtesy of my teacher wife, I call this game "Back-to-back" and it's a firm favourite with my kids.
1. Students stand in pairs; an odd student can stand and play with teacher.
2. Instruct students to stand with their backs touching and say "That's Back-to-back".
3. Students stand facing each other - "Front-to-front".
4. Students stand beside each other - "Side-to-side".
5. Each faces each other and moves one foot forward to touch toes - "Foot-to-foot".
6. Each touches an index finger to the other - "Finger-to-finger".
Teacher then issues random 'orders' of "finger-to-finger', "Foot-to-foot" etc. etc. at various speeds or in quick succession. Once students are confident or bored, throw in mixed orders such as "Back-to-front", "Side-to-finger" etc. and let them sort it out!