While describing a temple built by Solomon, the Bible appears to imply that pi equals 3. This is 1 Kings 7:23:
These figures are repeated at 2 Chronicles 4:2. If these measurements were exact, then pi would be 3. However, this is probably just a problem introduced by the author rounding to the nearest neat figure.
If that doesn't satisfy, Answers In Genesis has a more involved solution that uses the precise shape of the vessel, which according to 1 Kings 7:26 was like a cup. If this means it was flared at the top, then the discrepancy in the measurements can be explained away, as shown here.
But I find the rounding explanation much simpler.