There are tons of things to do for a team. Here is a small list for the team:
1-Close open issues (if any) in the projects delivered (if this is in your scope of work)
2-Prepare write-ups about mistakes in the last project(s) and how to avoid them in the future
3-Prepare educational sessions about new features in the tools that are useful but never found the time to use
4-Research best practices in different aspects of software development relevant to your software tools
5-Consider automation of repetitive tasks by building small utilities or templates
6-Research on new tools in the market that can make the next development faster and better
7-Ask the more experienced developers to teach the juniors some useful techniques
8-Attempt to do some team bonding and team building activities
9-Let people know more about each other's roles. Let developers see what DBAs do more closely and what issues they face. You may find that some of your developers could fill up for a dba for a holiday or so
10-Review your coding standards, backup strategy, disaster recovery, licenses, etc.
11-Study problems faced by the team members in detail and put plans to fix them
12-Consider building or using a Wiki for the team
13-Polish your company's web site