Put this script in your working dir and run it at the end of the day to remind you what you've done (+ some other git useful commands)

list_today.py

#!/usr/bin/python
 
import os, fnmatch

# Some useful git commands to choose from:
reposNotCommited = 'git --no-pager log --branches --not --remotes --simplify-by-decoration --decorate --oneline'
logEntriesToday = 'git --no-pager log --since="6am"'
logEntriesLastSemester = 'git --no-pager log --since="2014-01-01" --until="2014-06-30" --oneline --author="Jon Doe"'
logEntriesThisWeek = 'git --no-pager log --since="last sunday"'

# The git command of your choice:
theGitCommand = logEntriesThisWeek

# Some terminal colors to choose from:
class bcolors:
    HEADER = '\033[95m'
    OKBLUE = '\033[94m'
    OKGREEN = '\033[92m'
    WARNING = '\033[93m'
    FAIL = '\033[91m'
    ENDC = '\033[0m'

basePath = os.getcwd()

# Walk the sub-directory tree and run the git command wherever we find a git repo
for root,dirs,files in os.walk("."):
    for name in dirs:
        if fnmatch.fnmatch(name,".git"):
            os.chdir(root)
            output = os.popen(theGitCommand).read()
            if len(output)>0:
                print ">> " + bcolors.HEADER + root + bcolors.ENDC
                print bcolors.OKBLUE + output + bcolors.ENDC
            os.chdir(basePath)

Updated it to include a few more command examples