# Create new WIP branch off master:
git checkout -b hudsonBuild-someWIP --track origin/master

# Make experimental changes, commit them.

# Push upstream:
git push origin hudsonBuild-someWIP

# Hudson sees the branch appear and automatically builds the code.

# If you like the changes and want them on master, do this:
git checkout master
git merge --ff-only hudsonBuild-someWIP

# Whether you keep the changes or not, prune the branch from the remote server (note the colon):
git push origin :hudsonBuild-someWIP

# Switch back to master and delete the WIP branch:
git checkout master
git branch -d hudsonBuild-someWIP