No, not only on delete. I can reproduce it by attempting an update which receives a (400) Bad Request. I do have some code that can consistently produce a bad request (lol!).

Subsequent queries run ok (or it could be a case of the "every other" syndrome - see http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=423016&SiteID=1) , but updates and deletes fail. I did a quick check, and sure enough, there are sockets left open. Here is a partial display of netstat -a AFTER my program has terminated:

TCP MYMACHINE:1607 64.233.187.19:http ESTABLISHED TCP MYMACHINE:1608 64.233.187.19:http ESTABLISHED

In order to be able to update again, I have to reset my network card.

Here is a "SaveToXml" output of the entry that generates the 400 error:

<entry xmlns="http://www.w3.org/2005/Atom"><gd:eventStatus value="http://schemas.google.com/g/2005#event.confirmed" xmlns:gd="http://schemas.google.com/g/2005" /><gd:comments xmlns:gd="http://schemas.google.com/g/2005"><gd:feedLink href="http://www.google.com/calendar/feeds/cabosan%40gmail.com/private/full/mt5cdaajeede7ktr598mv0r47g/comments/" /></gd:comments><gd:when startTime="2006-07-07T00:00:00-05:00" endTime="2006-07-08T00:00:00-05:00" xmlns:gd="http://schemas.google.com/g/2005" /><gd:reminder minutes="10" xmlns:gd="http://schemas.google.com/g/2005" /><gd:transparency value="http://schemas.google.com/g/2005#event.opaque" xmlns:gd="http://schemas.google.com/g/2005" /><gd:visibility value="http://schemas.google.com/g/2005#event.default" xmlns:gd="http://schemas.google.com/g/2005" /><title type="text">My date 001</title><id>http://www.google.com/calendar/feeds/cabo...@gmail.com/private/full/mt5cdaaje...@</id><link href="http://www.google.com/calendar/event?eid=bXQ1Y2RhYWplZWRlN2t0cjU5OG12MHI0N2cgY2Fib3NhbkBnbWFpbC5jb20" rel="alternate" type="text/html" title="alternate" /><link href="http://www.google.com/calendar/feeds/cabo...@gmail.com/private/full/mt5cdaaje...@" rel="self" type="application/atom+xml" /><link href="http://www.google.com/calendar/feeds/cabo...@gmail.com/private/full/mt5cdaajeede7ktr598mv...@" rel="edit" type="application/atom+xml" /><link href="rs:Origin:Google://http://www.google.com/calendar/feeds/cabo...@gmail.com/private/full/mt5cdaaje...@" rel="related" type="text/html" /><author><name>John Lucas</name><email>John Lucas</email></author><category term="http://schemas.google.com/g/2005#event" scheme="http://schemas.google.com/g/2005#kind" /><summary type="text">My date 001</summary><content type="text" /><updated>2006-07-07T20:25:46-05:00</updated><published>2006-07-07T20:25:46-05:00</published></entry>