A note on line-breaks and indentation in VB to maximise readability:

gistfile1.vb

' Single-line lambdas:

_myService.MyMethod(userId, profileId,
    Sub(message As EventArgs) _eventAggregator.SendMessage(message))

' Multi-line lambdas: align `Sub` and `End Sub`:

_myService.MyMethod(userId, profileId, Sub(message As EventArgs) 
                                           _eventAggregator.SendMessage(message)
                                           _localVariable = e.Result
                                       End Sub)

' … the IDE should do this automatically for you.
' Of course, this is quite a huge level of indentation, you can dedent the whole block:

_myService.MyMethod(userId, profileId,
                    Sub(message As EventArgs) 
                        _eventAggregator.SendMessage(message)
                        _localVariable = e.Result
                    End Sub)

' (note the alignment to the opening parenthesis of the surrounding parameter list)
' … or even:

_myService.MyMethod(userId, profileId,
    Sub(message As EventArgs) 
        _eventAggregator.SendMessage(message)
        _localVariable = e.Result
    End Sub)