Here is a little jewel I came across when attempting to repair a disk with a corrupted journal.

# e2fsck /dev/hdb1
fsck 1.38 (30-Jun-2005)
e2fsck 1.38 (30-Jun-2005)
/dev/hdb1 contains a file system with errors, check forced.
Pass 1: Checking inodes, blocks, and sizes
Inode 8 has illegal block(s). Clear<y>? yes

Illegal block #8559 (1073741824) in inode 8. CLEARED.
Illegal block #8567 (1073741824) in inode 8. CLEARED.
Illegal block #8575 (1073741824) in inode 8. CLEARED.
Illegal block #8583 (1073741824) in inode 8. CLEARED.
Illegal block #8591 (1073741824) in inode 8. CLEARED.
Illegal block #8599 (1073741824) in inode 8. CLEARED.
Illegal block #8607 (1073741824) in inode 8. CLEARED.
Illegal block #8615 (1073741824) in inode 8. CLEARED.
Illegal block #8623 (925040641) in inode 8. CLEARED.
Illegal block #8631 (1073741869) in inode 8. CLEARED.
Illegal block #8639 (1073741824) in inode 8. CLEARED.
Too many illegal blocks in inode 8.
Clear inode<y>? yes

Restarting e2fsck from the beginning…
/dev/hdb1 contains a file system with errors, check forced.
Pass 1: Checking inodes, blocks, and sizes
….
Continues indefinitely

# tune2fs -f -O  ^has_journal /dev/hdb1
tune2fs 1.38 (30-Jun-2005)
Illegal block number passed to ext2fs_unmark_block_bitmap #1073741824 for block bitmap for /dev/hdb1
Segmentation fault

That led to a quite a chuckle. Thankfully debugfs did not exhibit the same insanity.

# debugfs -w /dev/hdb1
debugfs: feature -has_journal

# fsck -yf /dev/hdb1
# fsck -c /dev/hdb1

# tune2fs -j /dev/hdb1

Inode 8 contains the ext3 journel, so ripping it out allowed the fsck to run.