errr, ok in that case i dont really know, i'm not sure i can really think of anything that would help and that would be strong enough to hold the strings down- you might just have to keep playing songs where you don't need to change the key until you can get one, i'd say just have a play around with some things and see if you can find something that works.
you don't have to use one you could find music for songs that hav barcords so you don't need one. its more hard then if u hav a capo but it works
make a cappo out of something instead of buying one coz im broke atm and the music shop that i usually use has closed down ¬_¬
i used a rubber coated torch and tied it to the guitar neck with some wire i found (: it worked :D
I dont think there is anything. Maybe a clothes pin if you have find a big and long enough one.
what you thinking when you say improvise??
***have or can find...