Mnemonic devices are memory techniques that make it easier to memorize something because you are able to associate it with something else. A mnemonic can be an acronym, a sentence, word or picture. These can be silly or non-nonsensical as long as they fulfill the goal of reminding the students what they need to remember. For example, using the phrase, "Christopher Columbus said 'oh, hi' when he reached Ohio" can help students remember the capital of Ohio is Columbus.
Have the students create mnemonics for different state and capital pairs but instruct them not to share their mnemonics with their classmates. When they are finished and there is at least one mnemonic for each state and capital, read the mnemonics one-by-one to the entire class and have the children figure out which state and capital is being referenced.
Have a classroom poetry contest. Have each of the students write either limericks or haikus for each state that will help them remember the state name and capital. Encourage the students to make the poems as silly as possible. When all the students have finished their poetry, go state by state and ask for volunteers to read their poem for that particular state. The children can vote on which poem is the funniest or the most helpful in remembering the state. Although the poems can help trigger the children's memory, the act of writing them, reading them aloud, listening to the other student's poems and voting on the best will likely be all the children need to memorize all or most of the states.
If you do not want to task the students with each writing 50 poems, you can give each student a smaller set number. Then when all the students are finished, you can photocopy the poems and create state and capital poetry books for the entire class. Either way, this is a fairly large endeavor and will likely involve both in-class work and homework.
Have a set of cards with the names of all the states on them and a second set of identical cards with the names of all the capitals on them. Play the game like regular concentration, except the children are trying to match the state with the appropriate capital.
Because there will be a total of 100 cards, you may want to start out with a limited number of states and capitals or play with batches. This will make the games go quicker, and prevent the children from losing interest.
Two students start at the back of the classroom side by side. The teacher will stand at the front of the classroom with a tape line on the floor directly in front of her. The teacher will then either say the name of a state or show a card with the name written out. The first student to correctly yell out the capital of that state gets to take one giant step forward. This continues until one of the students steps on the tape line.
The teacher can alternate showing the states or the capitals or the teacher can mix them up so on each round the students will not know if they need to remember the state or the capital. Once a student wins a game, two new students get a turn. Each game can be done independently, or it can be played as a tournament, with the winners of each game then competing against each other.