This one is short and sweet.
Is your traceroute responding with "* * *", or did you enter 1000000000 for the number of extended pings?
Easy - simply type CTRL-SHIFT-6 to break the process.
That is the Control Key (hold down), the Shift Key (also hold down) and the "6" key - all at the same time.
From the Cisco documentation:
“The escape character (or key sequence) suspends any actively running processes and returns you to privileged EXEC mode or, if a menu is being used, to the system menu interface. The escape character is used for interrupting or aborting a process started by previously executed command. Examples of processes from which you can escape include Domain-Name lookup, ping, trace, and Telnet sessions initiated from the device to which you are connected. To send an escape sequence over a Telnet connection, press Ctrl-Shift-6 twice.”
“To define a system escape character, use the escape-character command in line configuration mode. To set the escape character to Break, use the no or default form of this command.”
“The default escape key sequence is Ctrl-Shift-6 (Ctrl-^) or Ctrl-Shift-6, X (^^X). The X is generally only required for modem connections.”
Hope that helps!