1. Yourself -- you cannot participate remotely.
2. Two forms of positive picture ID -- your driver's license, NUS card, passport for example. If you only have one form of picture ID with you you can still attend the party, but individuals may be less prepared to certify your identity and you may leave with considerably fewer signatures than you were hoping for.
3. Key ID, Key Type, Hex Fingerprint and Key Size info (the output of gpg --fingerprint <your-id>).
4. A pen or pencil.
Do not bring a computer to the event, because use of a computer for key signing would be an easy way for an unscrupulous person to compromise the security of the event.