Not sure this is the "correct" way to do it but it works.
RewriteCond %{QUERY_STRING} ^lob=value1$ [NC]
RewriteRule ^products.asp$ http://example.org/sample/one/? [R=301,L]
And then for a different value:
RewriteCond %{QUERY_STRING} ^lob=value2$ [NC]
RewriteRule ^products.asp$ http://example.org/sample/two/? [R=301,L]
And then for everything that doesn't match a value:
RewriteRule ^products\.asp$ [insert new url here] [R=301,L]
The last example also works if you just want to redirect a .asp url to .php. Keep in mind that I have other conditions and rules that are removing the .php extension and adding a / to all files:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+)/$ $1.php
RewriteRule ^([^/]+)/([^/]+)/$ /$1/$2.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !(\.[a-zA-Z0-9]{1,5}|/)$
RewriteRule (.*)$ /$1/ [R=301,L]