Have all of your first-graders get into a circle; they can either sit on the floor or pull their desks around. Direct one student to stand up behind a seated child. Pull out a flashcard with a sight word printed on it. The first of those two children to say the word correctly wins the round and moves on to challenge the next student in the circle. The first student to make his way around the entire circle of students (around the world) wins the game.
Write all of the sight words your class has learned on separate flash cards. Put all the cards into a hat. Have each child reach into the hat and pick out a single flash card. All of the children who can read their sight words get to keep them. The ones who can't have to return them to the hat. When the hat is empty, the child with the most sight cards in her hand wins the game. Oh, there's a twist. Write the word "BANG!" onto one of the flash cards. Any time a child pulls the card with this word out of the hat, he has to put all of his flash cards back into the hat.
This is a spin on a classic. Distribute bingo cards that have sight words printed on them, four words across and four words down. Place flash cards with those same words written on them into a box. One by one, reach into the box and pull out a flash card. Show the card to the students, read the word aloud, and then use it in a sentence. While you are doing this, students should place their bingo markers on the correlating word on their bingo cards. The first student to completely fill her card wins.
Split your first-graders into two groups. Distribute a stack of sight word flash cards to the students; the words should be exactly the same for both groups. Tell the students to make as many sentences out of the words as they can in two minutes. The group with the most sentences wins the game.