Bulletin Boards, This idea is not all that creative, but easy to maintain and the kids (and parents!) love it.  You'll need one of the bigger boards. After putting up your bulletin board paper(preferably a darker color) and border, use white yarn to section off a separate square for each child, like a tic-tac-toe board only longer. Label each square with a child's name.  Use one of the middle squares for your title.  I used a star border and some extra stars sprinkled about and titled it All-Star Work.  The kids can choose an item they are particularly proud of and post it.<BR>Change as desired.  That way your board doesn't always look the same, but doesn't require a lot of preparation on your part.  Plus, the kids love choosing and displaying their favorite work samples.

Backgrounds for bulletin boards
While this is not a decorative board, I use colored felt for my word wall.  If you put velcro on the backs of your words (laminate them first), they stick well and are easy to remove when a child needs to copy them 'cause they can take them to their seats (great for the little ones in Kinder or First who have a hard time finding and copying things from the board).  ;-D

A  year long wall decoration from the kids
At the beginning of each month the students write. They can write about anything they want as long as it's school appropriate. Be sure to have each name and date their samples. I make a wall space/ bulletin board with a single paper size space for each student. I personally just have a trim around the outside and have the papers hanging. (nothing fancy) Each month I add the latest sample on top of the other examples. During the year, I use the wall to illustrate growth, for conferences, etc. At any time you can walk over with a parent and they can see their child's progress. In June I take all the samples, bind them and give them to the parents as a gift. I have done this for years, it's greatly appreciated by kids and parents alike. After years of doing this, here's a couple of clues make sure the papers are not low on the walls being there all year they might get ruined and I only push pin on the top of the papers so one can easily flip back to September at any time.

Boggle Bulletin Board
Boggle bulletin board is similar to the game boggle.  You take 20 pieces of white paper, about 10 in. by 5 in. (the size of paper depends on how much space you have).
On each piece of paper you write a letter from the alphabet.  You arrange the 20 white squares in the shape of a large square. 
Students take a piece of paper and try to create words out of the bulletin board.  You can set a timer or not.  I usually let the students decide. You can make up your own rules as to what order the letters have to be arranged.
I usually say that the letters have to be touching to create the word.  But as the students play more, I pretty much let them create their own rules.
This can be played in groups or partners.  Each group, individual, or partner set tries to spell the most words. The students really enjoy this game.