Ecosystem Balderdash (also known as Biome Balderdash) is a fun interactive alternative to looking up definitions in the dictionary. It contains 18 words all related to ecosystems, habitats and biomes. To do all 18 words it takes about 2 hours. I usually pick and choose which words I would like them to focus on during the learning cycle and complete the game in 1 hour.
Basically, the students, working in groups of 3 or 4, create a definition for the word that other students will think is the actual definition. As a teacher, you also include the actual definition. Groups of students obtain points based on how many votes their definition receives and whether they choose the correct definition.
This file is a keynotes version of the game. A powerpoint version is also available. The very last slide contains some Teacher suggestions.