Use case scenarios for Access Control List

Hi I need some use case scenarios for an ACL implemented based on Layer 2 and Layer 3 header for an IP DSLAM. Can any body give some diagrammatical examples. Or else the theoritical scenarios

[10.0.0.0/8] ---> 192.168.1.0/24

10 clients on 10.x.x.x
10 clients on 192.168.1.x

Allow 10.0.0.1 to connect to 5 clients on the other subnet
Allow 10.0.0.2 to connect to all clients over port 80 (Layer 4 )
Deny 2 192.168.1.2 and .3 to connect to 10.0.0.3
Deny the rest.

Simple scenario, but gives you the idea of ACL

Hi,
This is fine. But I wanted to know some higher level idea of the ACL. Some practical scenarios in which the ACL can be applied.

for eg: Blocking some malicious user based on his Source MAC Address.