Apart from Word-Building, here are a few other word games that can be conducted in the class-room.
For these games, divide your class into groups of 6 (don't form more than 5 groups).
Call the first team to the front and make them decide an order to speak in. Give them a starting word.
The team is to form a chain of words, such that each team member speaks a word one by one and the next word should always begin with the letter the last word ended on. The team which makes the maximum number of words in a minute wins. You can set a limit for the shortest word allowed.
Variations: You can make it tougher by limiting them to speak words related only to a theme.
Dumb charade is a famous game in which one person of a team is given a movie and the rest of the team is supposed to guess the name, while this person enacts the name. You can use this one to teach a vocabulary of adjectives, professions, moods, expressions, characters of a story etc. Give one person from each team one profession, and the rest of the team must guess through his acting. The actor must not speak. Impose a time limit, depending on the difficulty you want to keep.
Write down a large word on the board, that has a substantial number of vowels. Ask each team to make three or more lettered words out of the word you have given. Set a time limit. The team that makes the maximum number of words wins. There could be a tie. So keep a bonus word ready and see which team makes higher number of words in a very short duration, say 10 seconds.
This game need not be played in a team. Decide an order to go in. Start with a word. The next word cannot be anything related to the word spoken right before. The word has to be spoken immediately. If one does not speak immediately or speaks a related word, he is out of the game. Moderate the game whenever required on issues of deciding whether or not a word is related.
Variation: The next word is totally unrelated to any of the previous spoken words. This would make it tougher.
Here is an example: say the person before me said "fan." So all electrical appliances, all big celebrities (since a fan is related to them), air, etc. are excluded for me.
That's about it. Hope you have fun using these creative teaching ideas in your class!