Reiser4, a.k.a wife killer fs + GRUB
Here it is, I won't warn you about nothing, if you don't know what the hell are you doing, don't do it!

Create >20mB ext2 partition and mount as /boot
I'll say /boot as sda1 and root directory (/) is sda3

mkdir testing
sudo mount /dev/sda1 testing
sudo cp -aR /boot/* testing/
sudo umount testing
rmdir testing

Now boot sda1 as /boot :

sudo mount /dev/sda1 /boot

Real shit:
What you need:
grub-0.97 [link]
libaal-1.0.5 [link]
reiser4progs-1.0.5 [link]
grub-0.97-libaal-1.0.5-reiser4progs-1.0.5.patch [link]

Create a seperated /grub directory and untar all of this into grub dir.

Note: if your box is x86_64, don't forget export that m32 shit:
export CC="gcc -m32"

exporting temporary LDFLAGS:

export LDFLAGS=-L/grub/r4/lib CPPFLAGS=-I/grub/r4/include

We'll create a directory (like r4) and install into this. First, aal libraries:

cd /grub/libaal-1.0.5
./configure --prefix=/grub/r4
make
make install

Now our old reiser4progs:

cd /grub/reiser4progs-1.0.5
./configure --prefix=/grub/r4
make
make install

go into grub dir:

cd /grub/grub-0.97

patch:

patch -p1 < ../grub-0.97-libaal-1.0.5-reiser4progs-1.0.5.patch

and compile (look, this time prefix=usr)

./configure --prefix=/usr
make

Control:

ls /grub/grub-0.97/stage2/*1_5

if you see the stage files, you can OVERWRITE:

make-install

Last one, re-write grub:

grub-install /dev/sda

And edit /boot/grub/menu.lst if neccesary.

Reference: [link]