Mine aren't web sites but rather a couple of IPTables rules themselves:
# --- Log blocked on input:
-A INPUT -j LOG --log-prefix "BLOCK_IN: " --log-level info
-A INPUT -j DROP
# --- Log blocked on output then drop everything not listed above:
-A OUTPUT -j LOG --log-prefix "BLOCK_OUT: " --log-level info
-A OUTPUT -j REJECT
# --- Log new connections:
-A INPUT -m state --state NEW -j LOG --log-prefix "NEW: " --log-level info
they will write to
/var/log/messages like so:
Feb 17 19:33:01 test001 kernel: BLOCK_IN: IN=eth0 OUT=\ MAC=00:0c:29:e6:35:ef:00:50:56:c0:00:02:08:00 SRC=10.0.0.1 \
DST=10.0.0.20 LEN=60 TOS=0x10 PREC=0x00 TTL=64 ID=7834 DF \
PROTO=TCP SPT=52196 DPT=1522 WINDOW=5840 RES=0x00 SYN URGP=0
Once you get use to looking for the BLOCK_IN/BLOCK_OUT and the DPT (Destination Port) you start to understand a lot of what the rules are doing. Watch what happens when you nmap it from another machine and so on.
VMWare/Virtual PC environments are also perfect for this kind of hands on learning.