SQL Server 2008 R2 XML to Relational Data

I don't know a lot about XML and even less about the XML data type in SQL Server 2008 R2. I have been reading a lot of posts and trying to understand them but, I confess, I'm now totally confused.

I have the following XML in a column called 'MatchData':

<ScheduleDefinition xmlns:xsd="http://ift.tt/tphNwY" xmlns:xsi="http://ift.tt/ra1lAU">
  <StartDateTime xmlns="http://ift.tt/16qqYsx">2014-02-07T08:05:00.000+00:00</StartDateTime>
  <WeeklyRecurrence xmlns="http://ift.tt/16qqYsx">
    <WeeksInterval>1</WeeksInterval>
    <DaysOfWeek>
      <Monday>true</Monday>
    </DaysOfWeek>
  </WeeklyRecurrence>
</ScheduleDefinition>

I've tried the following:

;with cte as (
select top 1
            SubscriptionID,
            [MatchData] = cast(MatchData as XML)
from        dbo.Subscriptions
)
select      MatchData.value('ScheduleDefinition[1]', 'varchar(max)') as XMLValue
from        cte

But it gives me every element value as a single, concatenated varchar:

2014-02-07T08:05:00.000+00:001true

WTF?

Please can anyone show me (and explain, if it's not too much trouble) how I extract each of StartDateTime, WeeksInterval and Monday into 3 separate columns?