Switch Git branch without files checkout

Yes, you can do this.

git symbolic-ref HEAD refs/heads/otherbranch

If you need to commit on this branch, you'll want to reset the index too otherwise you'll end up committing something based on the last checked out branch.

git reset

Using basic git commands only:

This answer is a bit longer than that of Charles, but it consists solely of basic git commands that I can understand and thus remember, eliminating the need to keep looking it up.

Mark your current location (commit first if needed):

git checkout -b temp

Reset (moves) the marker to the other branch without changing working dir:

git reset <branch where you want to go>

now temp and other branch point to the same commit, and your working dir is untouched.

git checkout <branch where you want to go>

since your HEAD is already pointing to the same commit, working dir is not touched

git branch -d temp

Note that these commands are also readily available from any graphical client.