The Plumtree portal implementations I have worked on have used VB/ASP as the medium between the user and the portal database in almost every situation. A digestable example of some ASP functions I wrote to format on a web page phone numbers with Siebel's masking. The numbers arrive from the database looking like this: +61414623689~0 0000 0000 and get formatted by my code to look like this: +61.4.1462.3689
Some useful ASP.NET code of mine is a Plumtree portlet delivering XML RSS newsfeeds as standard HTML to users. My experience with ASP.NET is limited.